As a method for drawing or expressing an image at a desired size, vector graphics is known. Vector graphics is one of the image formats used for computer graphics, and defines an image by utilizing outline information and plane information. Outline information defines the position of the starting point, the position of the ending point, and the attributes of lines. Plane information defines the attributes (colors and the like) of the plane enclosed by the outline. As has been described, according to vector graphics, since an image is defined in the form of numerical data, the data amount of an image is reduced compared with raster graphics. Also, vector graphics images do not deteriorate as easily in quality as compared to raster graphics images, when the size is changed.
When a vector image is to be drawn, a process of calculating coordinates through which the outline passes, a process of calculating an area to be filled in with color, and calculations of the color of the outline (anti-aliasing, for example) are executed. Accordingly, a vector image requires a greater amount of computation for generating image data than a raster image requires, and it takes long period of time to draw a vector image on a display device. Accordingly, techniques to reduce the period of time required to draw a vector image have been proposed.
In a method for processing figures according to a related art, to each pixel, control information indicating whether that pixel is a “left side edge point”, a “right side edge point” or “not an edge point” of a colored area is added. Thereafter, the control information of each pixel is referred to in horizontal scanning, and pixels located between the left side edge point and the right side edge point are colored in with a specified color. Thereby, a filling process is executed at a higher speed (Japanese Patent No. 2681367, for example).
As another related art, a method related to a speeding up of a filling processes is proposed (Japanese Patent No. 3249096). Also, a technique of drawing an anti-aliased outline at high speed is described (Japanese Laid-open Patent Publication No. 2002-56395, for example). Further, related techniques are described also in Japanese Laid-open Patent Publication No. 2006-209654, Japanese Laid-open Patent Publication No. 5-35879, Japanese Laid-open Patent Publication No. 60-163164, and Japanese Laid-open Patent Publication No. 6-4679.
However, when a multicolor vector image is to be drawn according to conventional techniques, a plane is necessary for each color and a scan conversion process for each plane is also necessary. In other words, a great amount of processing is required to process a multicolor vector image. Accordingly, in an information processing device with poor resources such as a mobile phone terminal, drawing a multicolor vector image requires a long period of time.